A. Field of the Invention
The present invention relates to a disposable unitary plastic base mold made from a sheet of plastic material and adapted to receive a biological tissue specimen and to support a tissue processing cassette or a tissue processing embedding ring. A solidifiable fluid embedding material, such as paraffin, is poured into the mold through the cassette or through the embedding ring and the embedding material is allowed to solidify in order to encapsulate the specimen and fix the tissue specimen to and adjacent an outer bottom surface of the cassette or embedding ring.
B. Description of the Prior Art
Heretofore, various molds for embedding tissue specimens therein have been proposed. Examples of such previously proposed molds are disclosed in the following U.S. Pat. Nos.:
______________________________________ Re. 28,165 McCormick 2,718,126 Ball 3,014,614 Carroll, et al 3,483,908 Donovan 4,272,049 Kindel ______________________________________
The McCormick U.S. Reissue Pat. No. Re. 28,165 discloses a biological specimen processing and embedding apparatus comprising a combination capsule and base mold apparatus for treatment of a biological specimen. The base mold is formed from metal and has a generally open-top box-like rectangular shape into which a multi-purpose capsule and open mold member is received. The base mold includes a flat bottom wall, two transverse side walls, two longitudinal side walls, and an open top, the upper portion of the side walls being offset outwardly to form an angular horizontal surface or ledge with the open top.
The Ball U.S. Pat. No. 2,718,126 discloses an ice mold for dental use made of plastic or rubber for the formation of ice cubes of a configuration substantially similar to that of the prescribed areas of the mouth in order that it may be inserted into the patient's mouth. More particularly, the mold is formed with a recessed portion or cavity having a configuration of the arc of a circle, a recessed portion having a configuration of greater curvature substantially approaching a semi-circular shape, and a third cavity having a substantially rectangular shape, all having a substantially rounded or concaved bottom adapted to be filled with water and placed in a freezing compartment.
The Carroll, et al U.S. Pat. No. 3,014,614 discloses a disposable plastic mold adapted for embedding samples of tissue in paraffin wherein the molded material can be easily and quickly removed. The disposable mold comprises a plurality of rectangular mold containers, or cups, each having an open upper surface and are joined in clusters of twelve containers by joining straps which connect each of the containers to each adjacent container. If the material is to be formed while the containers are resting upon their bottom surfaces, protrusions are formed on the lower walls of each of the containers in order to facilitate resting of the containers on a planar surface.
The Donovan U.S. Pat. No. 3,483,908 discloses a flexible container including a side wall provided with a series of substantially parallel ribs which provide increased resistance to deformation in the lateral direction. A bottom wall is also provided having a spiral groove spiralling outwardly from the center of the bottom wall to provide a discharge means in combination with the ribbed wall for removing a substantially solid substance, such as a cupcake, from the container by pressing the bottom wall of the container upwardly.
The Kindel U.S. Pat. No. 4,272,049 discloses a mold for molding specimen blocks to be cut in a microtome or an ultramicrotome. The mold comprises a plate which is made from a heat resistant plastic and which has a number of cavities open at their ends. The cavity has a general cylindrical shape. A transparent bottom wall is provided for examination of the tissue specimen therein and which is thin enough so that it can be deformed easily to remove a molded block therefrom when subjected to finger pressure.
In addition to the molds described above, other disposable specimen molds have been proposed which are formed from a single sheet of plastic material. Such a mold includes a planar sheet of plastic of a generally square or rectangular shape and having a centrally located recess or receptacle pressed from or formed in the sheet. The receptacle comprises four side walls and a bottom wall wherein the sole means of support for the mold is the bottom wall of the receptacle.
As will be described in greater detail hereinafter, the free standing base mold of the present invention differs from the various mold containers previously proposed by providing a base mold which includes means for sturdily supporting the base mold upon a planar surface, as well as means for receiving a biological tissue specimen and for supporting a tissue processing cassette or an embedding ring while a solidifiable fluid embedding material is poured into the mold and allowed to solidify in order to fix the tissue specimen to and adjacent an outer bottom surface of the cassette or the embedding ring.